Their mom, Whitney Meyer, said she considers the girls a symbol against racism and a sign to “love everyone equal.”

“You can’t look at one and not love them both,” she told TODAY. “They’re the same girl, just different colors.”

Meyer recalls the surprise she got when the girls were born last April 23 in Quincy, Illinois.

“Kalani was as white as can be. I was just in denial, because you know the odds of this?” she said. “I would never think I would have a black and white twin. That’s why I asked if she was albino, because she was just so white.”

Tomas Dean, Meyer’s boyfriend and the father of the twins, was just as surprised.

“I was like, ‘Yeah, she’s a little light,' but I thought maybe babies are that way when they’re first born. But then a couple of minutes later, her sister came out a little darker,” he said. “In a million years, I never thought I’d have a girl with blue eyes. I didn’t think I could pull that one off!”

Meyer said she usually dresses the girls in matching outfits.

“They look alike in their smiles, but I have to dress them the same because nobody believes that they are twins. I mean, nobody,” she said.

The parents of biracial sisters, Jarani, left, and Kalani, say few strangers realize the girls are twins.Whitney Meyer

The girls already have started demonstrating differences in their personalities. Kalani is more energetic and, after learning to crawl recently, loves to explore. Jarani likes to stay put.

“She’s the chunky one. She likes to be held and cuddled more than Lani,” said Meyer, who calls the girls her “miracle babies. They were born nearly two years after her 2-year-old son, Pravyn, drowned while under the supervision of his day care provider.

She said Jarani is the spitting image of Pravyn, who had darker skin like his dad, while Kalani looks like her 7-year-old Caucasian brother, Talan, who reads to the girls every night.

“He’s an amazing big brother,” Meyer said.

The twins with their parents and older half-brother, Talan.Courtesy of Whitney Meyer

It’s unusual for biracial siblings, particularly twins, to look as different as Kalani and Jarani, but there are so many genes that control skin tone and eye color, that even scientists don’t even know all the potential ways they can interact.

“The physical traits you can see in a person are just a very small sliver of the genetic diversity across human populations,” said Dr. Bryce Mendelsohn, a medical geneticist at the University of California, San Francisco. “A lot of times we only focus on the things our eyes can see, but what we see is a tiny tip of the iceberg of the actual genetic diversity in everyone.”

While certain physical traits may be more common in certain ethnic groups, the genes for most physical characteristics are usually present in all ethnicities, he said.

“When you flip a coin eight times, sometimes it’s going to be heads all eight times. And it’s kind of like that when you have a bunch of genes. They’re all randomly shuffling, and you can get all kinds of outcomes."

Khristi Cunningham knows this. The Ohio mother also has fraternal twins, one of each gender. And like Kalani and Jarani, one child is has darker skin and the other has light skin.

"No one on this Earth gets to stand in line to pick their skin color," says Khristi Cunningham, who has one black and one white twin children.Courtesy of Khristi Cunningham

When she heard about the Illinois twins, she thought: “Get ready for a lot of conversations with strangers!”

Cunningham is white, and her husband is black. While most people can tell their children are siblings, few pick up on the fact that they are twins. The children, now 7, received a lot of media attention as babies, but Cunningham didn't mind.

"We did feel that we were obligated to share our story with others. We felt we were given these two beautiful children for a positive purpose — that purpose was to educate those who are ignorant to the fact that these things are possible, and to initiate conversation on race in America," she told TODAY.

"Being a certain color is not an 'accomplishment,' or something to be 'proud of.' No one on this Earth gets to stand in line to pick their skin color. It is only by chance we are brown, or black, or white."

Kalani and Jarani's brother, Pravyn, who passed away in 2014 at age 2, is added to a family portrait. Courtesy of Whitney Meyer

Dean agreed. The proud new papa said he understands why people are intrigued by his twin daughters but wants people to look past their physical difference.

“I hope that a lot of people can see that color really isn’t a big thing. What's important is love," he said. "Mysterious things can happen and life is a blessing."